Temporarily disable the firewall to confirm the issue (do not do this in production).
# Test TCP port nc -zv <target-ip> <port> telnet <target-ip> <port> Test with curl (HTTP) curl -v http://<target-ip>:<port>
sudo ufw status verbose If inactive, enable it with sudo ufw enable . If active, check for rules like Deny from any or missing Allow rules for your port. inbound traffic blocked, check firewall settings
# Linux / macOS sudo netstat -tulpn | grep LISTEN # or ss -tuln netstat -an | findstr "LISTENING"
Chain INPUT (policy DROP)
If the service is not listening on the expected port, the firewall isn’t the issue. Linux (iptables / nftables / firewalld / ufw) Using iptables (legacy):
sudo iptables -L -n -v Look for a default policy of DROP or REJECT on the INPUT chain. Example blocking line: Temporarily disable the firewall to confirm the issue
sudo pfctl -s rules Disable temporarily:
